In airports, train stations and in other places of mass transportation for humans and for animals (‘subjects’), it is known to screen individuals or animals for elevated temperature or other signs of illness. This is done to curtail the spread of illness caused by infectious disease.
In the past, such screening was done initially through subjective observation. A screening officer would simply observe a subject and look for signs of illness such as sweating, disorientation, flushed skin tone and coughing as indications that such a subject is ill and should be isolated from other subjects passing through the transportation hub.
More recently, there have been several technologies developed for screening subjects by measuring temperature, because elevated body temperature is a strong general indication of illness, including some contractual illnesses in both humans and animals. Such technologies have included thermometers, but thermometers have been problematic in a high-volume screening environment for two reasons. First, they are slow to react, which increases the time to measure temperature and thereby also increases operator error. Second, thermometers are difficult to sterilize because they come into direct contact with the subject. The increased chance of erroneous measurements and the problems with sterilization thereby greatly increase the chance of the spread of some contractual illnesses.
There are temperature sensors which measure temperature less invasively than a thermometer by using infrared radiation to measure temperatures at very short distances. Some infrared thermometers operate by being in contact with the skin of the subject. Other infrared thermometers operate at a distance of a few inches from the forehead of the subject, or from other sensing zones of the subject.
One of the principal challenges of using such methods is testing large numbers of individual subjects passing through a transportation hub or other building for symptoms of illness. The process can be slow if each individual has to be tested separately.
Some prior art temperature sensing devices scan individuals automatically using infrared sensing technology, and retrieve the results. The scanning process is typically done by passing infrared radiation over the subject's body or portion of their body to measure their temperature. There are three main difficulties with such devices. First, they must typically be manually re-adjusted to accommodate subjects of different heights.
Second, because the focal lengths of the infrared sensors are fixed, subjects must stand within a specific distance range from the device in order to provide an accurate reading. Because there is no facility to measure accurately the subject's distance in existing devices, the subject and operator usually do not know if a reading is erroneous.
Finally, because the infrared device must pass across the subject in a scanning motion, performing the scan and producing results could take between approximately tens of seconds to several minutes.
This time frame is typically too long to effectively test large numbers of subjects and prevent the spread of disease, while maintaining flow through such facilities. There is therefore a need for a remote temperature sensing device that automatically tests the subject, but also automatically measures distance, and that further adjusts to accommodate the height of the subjects approaching the temperature sensor.